Maybe this sounds like a pipe dream, but is this something that could be technically possible ? The new a7R sounds like a perfect backup / companion camera to some medium format systems while on the go. Since the metabones speed booster takes a full frame lens and refocuses it for aps-c or MFT, could there not be one made that can take a full frame 645 lens and refocus it to full frame 35mm ? Carrying some medium format gear but not having to take another set of lenses if the main body fails would make a product like this very compelling.

Maybe this sounds like a pipe dream, but is this something that could be technically possible ? The new a7R sounds like a perfect backup / companion camera to some medium format systems while on the go. Since the metabones speed booster takes a full frame lens and refocuses it for aps-c or MFT, could there not be one made that can take a full frame 645 lens and refocus it to full frame 35mm ? Carrying some medium format gear but not having to take another set of lenses if the main body fails would make a product like this very compelling.

It should be possible, just a scaling issue. It certainly appeals to me, a Pentax 645 150mm f2 or a 300mm f2.8 would be very nice to have.

There are two kind of Metabone adapters. The Speedbooster type contains a lens system which reduces the focal length by factor 0.7 and this is for APS sensor mirrorless cameras only.The other ones are mechanical adapters with some electronic features (to transfer the EXIF, allow auto aperture and eventually autofocus). With these - like mentioned before - the only restriction could be the lack of sufficient back barrel clearance of the Metabone adapter.

I have the TSE lenses mentioned and I've already preordered the A7r. I'm going to add the novoflex adaptors for both Canon and Leica M. Hoping that the Leica 21 Super elmar will work well might be hoping for too much, but I can dream...

There are two kind of Metabone adapters. The Speedbooster type contains a lens system which reduces the focal length by factor 0.7 and this is for APS sensor mirrorless cameras only.The other ones are mechanical adapters with some electronic features (to transfer the EXIF, allow auto aperture and eventually autofocus). With these - like mentioned before - the only restriction could be the lack of sufficient back barrel clearance of the Metabone adapter.

Thanks...did not realize at first that there was a non-speedbooster version.

I have a question regarding dynamic range; does the new sony a7r have the same DR as the nikon d800? I was gonna buy the nikon but now might buy the sony, for my work DR is the most important factor.

To be really sure we need to wait for some tests, DxOmark being the most reliable source. But I would be *extremely* surprised if it has not as good DR.

If I would guess I think it will have slightly worse high ISO noise performance, but better color at base ISO, due to a different color filter tradeoff. We've seen this before when Nikon and Sony has used (almost) the same sensors but with slightly different color filters.

Sony has had the best sensors in the APS-C / 135 segment for a while, but not the best glass. Thanks to being mirrorless the possibilities through adapters is huge though, making this camera very interesting.

right, and this camera is pretty much as I would have done it if I had had the money to develop such a body.The point I would have done differently is the Finder, I think this should have been made removable, or at least "movable" with a tilting mechanism for some work.

This is a proof of concept and will probably be the first step of converting Photo Pros to mirrorless.

right, and this camera is pretty much as I would have done it if I had had the money to develop such a body.The point I would have done differently is the Finder, I think this should have been made removable, or at least "movable" with a tilting mechanism for some work.

I suppose being able to tilt the finder vertically would have been a good modification without compromising the camera's structure, but if it comes down to maneuvering the camera into tricky positions, it always supports the use of NFC or WiFi for phone/tablet tethering with liveview and camera controls available.

Right , of course you could use an external screen. You also can tilt the built in screen. But I´m an oldfashioned guy sometimes. I always had different finders for my cameras when they supported them,my Minolta XM. my Nikon F3, my Pentax 67, my Mamiyas 645 and RZ and I firmly believe it is the most intuitive way to focus when you can hold the camera with 2 hands and don´t have to handle additional stuff with my 3rd hand....(!) or remove it from my eye when I´m in "finder photo mode".

an MFDB is mirrorless. I can put my back on Hasselblad V or Hasselblad Flexbody. But I think that LV and EVF are missing components. Latest backs have some LV capability.

Best regardsErik

I think he meant something like a Mamiya 7, a fully integrated camera system, backs are mirrorless but also camera-less too, and if you put one on a camera they bulge out. You pay twice in size/weight for having electronics both in the camera and back, instead of a unified system.

I just had a thought - if Leica made the S system "built from the ground up" as a purely digital camera system, why did they have to make it an SLR? It's a concept that's analog in nature (getting around the capture medium), and it only seems they did that because they went with a CCD sensor. The 30x45mm size they picked isn't all that big, if they had ordered a custom-size CMOS chip, they could've had a fully electronic medium format camera by now.

Do you even need to go mirrorless to achieve this? most MF lenses have flange distances in the 65mm-85mm range and tilt/shift adapters already exist, I'm guessing that maybe enough space for a speed booster on a regular FF DSLR.